JP2012042927A - Zoom lens system, imaging apparatus, and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens system having a small F-number at the wide angle end and sufficiently applicable to wide-angle photography, and an imaging apparatus and camera including the zoom lens system.SOLUTION: A zoom lens system comprises, in order from an object side to an image side, a pre-group including a first lens group located closest to the object side and having a negative power as a whole, and a rear group having a positive power as a whole. At least the pre-group moves along an optical axis when zooming, and the first lens group is composed of three or less lens elements. The rear group has a lens group provided with an aperture diaphragm between lens elements which do not change an air interval when zooming, and a sub-lens group of a part of the lens group consisting the rear group moves in a direction perpendicular to the optical axis, the zoom lens system satisfying the following condition: 0.1<BF/f<2.0 (ω>72°, FNO<2.9, where BF is a back focus of the entire system at a wide angle end, fis a focal distance of the entire system at the wide angle end, ωis a field angle at the wide-angle end, and FNOis an F-number at the wide-angle end). In addition, an imaging device and a camera are provided.

Description

  The present invention relates to a zoom lens system, an imaging apparatus, and a camera. In particular, the present invention has a high-performance zoom lens system that is small, has a small F-number at the wide-angle end, and can be sufficiently adapted to wide-angle shooting, an imaging apparatus including the zoom lens system, and the imaging The present invention relates to a camera provided with a device.

  In recent years, solid-state imaging devices such as high-pixel CCD (Charge Coupled Device) and CMOS (Complementary Metal-Oxide Semiconductor) have been developed, and an imaging optical system having high optical performance corresponding to these high-pixel solid-state imaging devices has been developed. Digital still cameras and digital video cameras (hereinafter simply referred to as “digital cameras”) equipped with an imaging device are rapidly spreading. Among digital cameras having such high optical performance, demand for small digital cameras is increasing.

  The digital camera is required to be further downsized because it is easy to carry. In order to realize such a small digital camera, various proposals have been conventionally made.

  For example, in order from the object side to the image side, a front group having a negative power as a whole and a rear group having a positive power as a whole, the lens on the most object side during zooming from the wide angle end to the telephoto end Proposed zoom lens that has a lens group with an aperture stop between the lens elements that move the group and do not change the air spacing, and a part of the lens group included in the rear group moves to correct image blur Has been.

  Patent Document 1 has five lens groups, positive, negative, positive, positive, and positive that move during zooming in order from the object side to the image side, and a diaphragm is disposed between the lenses that form the third lens group, thereby reducing image blur. In order to correct, a zoom lens in which a part of the third lens group moves in a direction orthogonal to the optical axis is disclosed.

  Patent Document 2 has four positive, negative, positive and positive lens groups that move during zooming in order from the object side to the image side, and a diaphragm is disposed between the lenses constituting the third lens group to correct image blur. Therefore, a zoom lens in which a part of the third lens group moves in a direction orthogonal to the optical axis is disclosed.

  Patent Document 3 has four positive, negative, positive, and positive lens groups that move during zooming in order from the object side to the image side, and a diaphragm is disposed between the lenses constituting the third lens group to correct image blur. Therefore, a zoom lens is disclosed in which the entire third lens group moves in a direction orthogonal to the optical axis.

  Patent Document 4 has four positive, negative, positive and positive lens groups that move during zooming in order from the object side to the image side, and a diaphragm is disposed between the lenses constituting the third lens group to correct image blur. Therefore, a zoom lens in which a part of the third lens group moves in a direction orthogonal to the optical axis is disclosed.

  Patent Document 5 has four lens groups that are negative, positive, and positive that move during zooming in order from the object side to the image side, and a diaphragm is disposed between the lenses that form the third lens group, thereby reducing image blur. In order to correct, a zoom lens in which a part of the third lens group moves in a direction orthogonal to the optical axis is disclosed.

JP 2006-133582 A JP 2009-162862 A JP 2010-014844 A JP 2010-033087 A JP-A-11-231220

  However, the zoom lens disclosed in Patent Document 1 has a maximum angle of view of about 60 ° at the wide-angle end, and cannot satisfy the demand for a compact digital camera whose angle of view at the wide-angle end has been increasing in recent years. However, since the total lens length is fixed, the front lens diameter increases. Furthermore, since the back focus is long, the entire length of the lens becomes long, and the miniaturization is insufficient.

  Although the zoom lens disclosed in Patent Document 2 has a maximum angle of view of 70 ° at the wide-angle end, the ratio of the total lens length to the image height is as large as 20 times or more, and the size reduction is insufficient.

  Although the zoom lens disclosed in Patent Document 3 has a maximum field angle of 79 ° at the wide-angle end, the entire lens group is moved in a direction perpendicular to the optical axis in order to correct image blur. The mechanism for this will become large. The minimum F number is 3.28, which does not satisfy the requirement for a bright lens.

  The zoom lens disclosed in Patent Document 4 has an extremely large ratio of the total lens length to the image height of 20 times or more, and is not sufficiently miniaturized. Further, the maximum angle of view at the wide-angle end is 60 °, and the demand for a compact type digital camera whose angle of view at the wide-angle end has been increasing in recent years cannot be satisfied.

  Although the zoom lens disclosed in Patent Document 5 has a maximum field angle of 73 ° at the wide-angle end, the maximum F-number is as large as 3.8, which does not satisfy the requirement for a bright lens. Further, since the back focus is long, miniaturization is insufficient.

  An object of the present invention is, of course, a high-performance zoom lens system that is small and has a small F-number at the wide-angle end and can be sufficiently adapted to wide-angle shooting, an imaging device including the zoom lens system, and the It is to provide a camera provided with an imaging device.

One of the above objects is achieved by the following zoom lens system. That is, the present invention
A zoom lens system having a plurality of lens groups each composed of at least one lens element,
From the object side to the image side,
A front group including a first lens group located on the most object side and having negative power as a whole;
A rear group having positive power as a whole,
During zooming from the wide-angle end to the telephoto end during imaging, at least the front group moves along the optical axis,
The first lens group is composed of three or less lens elements,
The rear group has a lens group having an aperture stop between lens elements that do not change the air interval during zooming;
A sub-lens group of a part of the lens group constituting the rear group moves in a direction perpendicular to the optical axis to optically correct image blur;
The following conditions (1):
0.1 <BF / f _W <2.0 (1)
(However,
ω _W > 72 °
FNO _W <2.9
here,
BF: Back focus of the entire system at the wide-angle end,
f _W : focal length of the entire system at the wide-angle end,
ω _W : Angle of view at the wide-angle end,
FNO _W : F number at the wide-angle end)
The present invention relates to a zoom lens system that satisfies the above.

One of the above objects is achieved by the following imaging device. That is, the present invention
An imaging apparatus capable of outputting an optical image of an object as an electrical image signal,
A zoom lens system that forms an optical image of the object;
An image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
The zoom lens system is
Having a plurality of lens groups composed of at least one lens element;
From the object side to the image side,
A front group including a first lens group located on the most object side and having negative power as a whole;
A rear group having positive power as a whole,
During zooming from the wide-angle end to the telephoto end during imaging, at least the front group moves along the optical axis,
The first lens group is composed of three or less lens elements,
The rear group has a lens group having an aperture stop between lens elements that do not change the air interval during zooming;
A sub-lens group of a part of the lens group constituting the rear group moves in a direction perpendicular to the optical axis to optically correct image blur;
The following conditions (1):
0.1 <BF / f _W <2.0 (1)
(However,
ω _W > 72 °
FNO _W <2.9
here,
BF: Back focus of the entire system at the wide-angle end,
f _W : focal length of the entire system at the wide-angle end,
ω _W : Angle of view at the wide-angle end,
FNO _W : F number at the wide-angle end)
The present invention relates to an imaging apparatus that is a zoom lens system that satisfies the above.

One of the above objects is achieved by the following camera. That is, the present invention
A camera that converts an optical image of an object into an electrical image signal, and displays and stores the converted image signal;
An image pickup apparatus including a zoom lens system that forms an optical image of an object, and an image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
The zoom lens system is
Having a plurality of lens groups composed of at least one lens element;
From the object side to the image side,
A front group including a first lens group located on the most object side and having negative power as a whole;
A rear group having positive power as a whole,
During zooming from the wide-angle end to the telephoto end during imaging, at least the front group moves along the optical axis,
The first lens group is composed of three or less lens elements,
The rear group has a lens group having an aperture stop between lens elements that do not change the air interval during zooming;
A sub-lens group of a part of the lens group constituting the rear group moves in a direction perpendicular to the optical axis to optically correct image blur;
The following conditions (1):
0.1 <BF / f _W <2.0 (1)
(However,
ω _W > 72 °
FNO _W <2.9
here,
BF: Back focus of the entire system at the wide-angle end,
f _W : focal length of the entire system at the wide-angle end,
ω _W : Angle of view at the wide-angle end,
FNO _W : F number at the wide-angle end)
The present invention relates to a camera that is a zoom lens system satisfying

  According to the present invention, the zoom lens system, which is small in size, has a small F-number at the wide-angle end, and can be sufficiently adapted to wide-angle shooting, an imaging apparatus including the zoom lens system, and the A camera provided with an imaging device can be provided.

Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 1 (Example 1) Longitudinal aberration diagram of the zoom lens system according to Example 1 in an infinitely focused state Lateral aberration diagram in the basic state where image blur correction is not performed and in the image blur correction state at the telephoto end of the zoom lens system according to Embodiment 1 Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 2 (Example 2) Longitudinal aberration diagram of the zoom lens system according to Example 2 in an infinitely focused state Lateral aberration diagrams in the basic state where image blur correction is not performed and in the image blur correction state at the telephoto end of the zoom lens system according to Example 2 Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 3 (Example 3) Longitudinal aberration diagram of the zoom lens system according to Example 3 in an infinitely focused state Lateral aberration diagram in the basic state where image blur correction is not performed and in the image blur correction state at the telephoto end of the zoom lens system according to Example 3 Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 4 (Example 4) Longitudinal aberration diagram of the zoom lens system according to Example 4 in an infinitely focused state Lateral aberration diagrams in the basic state where image blur correction is not performed and in the image blur correction state at the telephoto end of the zoom lens system according to Example 4 Lens arrangement diagram showing an infinitely focused state of a zoom lens system according to Embodiment 5 (Example 5) Longitudinal aberration diagram of the zoom lens system according to Example 5 in an infinitely focused state Lateral aberration diagrams in the basic state where image blur correction is not performed and in the image blur correction state at the telephoto end of the zoom lens system according to Example 5 Lens arrangement diagram showing an infinitely focused state of a zoom lens system according to Embodiment 6 (Example 6) Longitudinal aberration diagram of the zoom lens system according to Example 6 in focus at infinity Lateral aberration diagrams in the basic state where image blur correction is not performed and in the image blur correction state at the telephoto end of the zoom lens system according to Example 6 Schematic configuration diagram of a digital still camera according to Embodiment 7

(Embodiments 1 to 6)
1, 4, 7, 10, 13 and 16 are lens arrangement diagrams of the zoom lens systems according to Embodiments 1, 2, 3, 4, 5 and 6, respectively, and all are in an infinite focus state. A zoom lens system is shown.

In each figure, (a) shows a lens configuration at the wide angle end (shortest focal length state: focal length f _W ), and (b) shows an intermediate position (substantially intermediate focal length state: focal length f _M = √ (f _W *). f _T )) lens configuration, (c) shows the lens configuration at the telephoto end (longest focal length state: focal length f _T ). Also, in each figure, the broken line arrows provided between FIGS. (A) and (b) are obtained by connecting the positions of the lens groups in the wide-angle end, the intermediate position, and the telephoto end in order from the top. Straight line. Therefore, between the wide-angle end and the intermediate position, and between the intermediate position and the telephoto end are simply connected by a straight line, which is different from the actual movement of each lens group. Furthermore, in each figure, the arrow attached to the lens group represents the focusing from the infinite focus state to the close object focus state. That is, the moving direction during focusing from the infinitely focused state to the close object focused state is shown.

  In FIGS. 1, 4, 7, 10, 13, and 16, an asterisk * attached to a specific surface indicates that the surface is aspherical. In each figure, a symbol (+) and a symbol (−) attached to a symbol of each lens group correspond to a power symbol of each lens group. In each figure, the straight line described on the rightmost side represents the position of the image plane S. Further, as shown in FIGS. 1, 4, 7, 13 and 16, in the third lens group G3, an aperture stop A is formed between lens elements that do not change the air interval during zooming from the wide-angle end to the telephoto end during imaging. Is provided. As shown in FIG. 10, in the second lens group G2, an aperture stop A is provided between lens elements that do not change the air interval during zooming. The aperture stop A moves on the optical axis integrally with two lens elements that are positioned immediately on the object side and immediately on the image side of the aperture stop A and do not change the air interval during zooming. .

  The zoom lens system according to Embodiment 1 includes a front group GA and a rear group GB in order from the object side to the image side. The front group GA includes a first lens group G1 and a second lens group G2 in order from the object side to the image side. The rear group GB includes a third lens group G3 and a fourth lens group G4 in order from the object side to the image side.

  As shown in FIG. 1, the first lens group G1 includes only a biconvex first lens element L1 having a positive power.

  The second lens group G2 includes, in order from the object side to the image side, a biconcave second lens element L2 having negative power, and a negative meniscus shape having negative power and a convex surface facing the object side. The third lens element L3 includes a positive meniscus fourth lens element L4 having a positive power and having a convex surface facing the object side. The third lens element L3 has two aspheric surfaces.

  The third lens group G3 has, in order from the object side to the image side, a positive meniscus fifth lens element L5 having a positive power and a convex surface facing the object side, and a biconvex shape having a positive power. A sixth lens element L6; a biconcave seventh lens element L7 having negative power; an aperture stop A; and a negative meniscus eighth lens element having negative power and having a convex surface facing the image side. L8 and a biconvex ninth lens element L9 having positive power. Among these, the sixth lens element L6 and the seventh lens element L7 are cemented. The sixth lens element L6 has an aspheric object side surface.

  The fourth lens group G4 comprises solely a positive meniscus tenth lens element L10 having positive power and a convex surface facing the object side.

  In the zoom lens system according to Embodiment 1, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves slightly toward the image side while drawing a convex locus on the image side, The second lens group G2 moves toward the image side along a convex locus on the image side, the third lens group G3 moves toward the object side monotonously, and the fourth lens group G4 moves toward the object side monotonously. To do. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. Each lens group moves along the optical axis such that the distance between the group G4 increases and the distance between the fourth lens group G4 and the image plane S increases.

  In focusing from the infinitely focused state to the close object focused state, the fourth lens group G4 moves to the object side along the optical axis.

  In the zoom lens system according to Embodiment 1, the fifth lens element L5, the sixth lens element L6, and the seventh lens element L7, which are some sub-lens groups of the third lens group G3, are orthogonal to the optical axis. By moving in the direction, image point movement due to vibration of the entire system can be corrected, that is, image blur due to camera shake, vibration, or the like can be optically corrected.

  In the zoom lens system according to Embodiment 1 and the zoom lens systems according to Embodiments 2 to 6 to be described later, the sub lens group is orthogonal to the optical axis when correcting the image point movement due to vibration of the entire system. By moving in the direction, it is possible to correct the image blur while maintaining excellent imaging characteristics with small decentration coma and decentering astigmatism while suppressing the enlargement of the entire zoom lens system and making it compact. Can do.

  In this specification, a partial sub-lens group of a lens group means that when one lens group is composed of a plurality of lens elements, any one of the plurality of lens elements or A plurality of adjacent lens elements.

  The zoom lens system according to Embodiment 2 includes a front group GA and a rear group GB in order from the object side to the image side. The front group GA includes a first lens group G1 and a second lens group G2 in order from the object side to the image side. The rear group GB includes a third lens group G3 and a fourth lens group G4 in order from the object side to the image side.

  As shown in FIG. 4, the first lens group G1 has a negative meniscus first lens element L1 having a negative power and a convex surface facing the object side in order from the object side to the image side. It has a positive meniscus second lens element L2 having power and having a convex surface facing the object side.

  The second lens group G2 has negative power in order from the object side to the image side, a negative meniscus third lens element L3 having a convex surface facing the object side, and a biconcave shape having negative power. It comprises a fourth lens element L4 and a positive meniscus fifth lens element L5 having positive power and having a convex surface facing the object side. The third lens element L3 has two aspheric surfaces.

  The third lens group G3 has, in order from the object side to the image side, a positive meniscus sixth lens element L6 having a positive power and a convex surface facing the object side, and a biconvex shape having a positive power. A seventh lens element L7; a biconcave eighth lens element L8 having negative power; an aperture stop A; a negative meniscus ninth lens element having negative power and having a convex surface facing the image side L9 and a biconvex tenth lens element L10 having positive power. Among these, the seventh lens element L7 and the eighth lens element L8 are cemented. The sixth lens element L6 has an aspheric object side surface, and the ninth lens element L9 has both aspheric surfaces.

  The fourth lens group G4 comprises solely a positive meniscus eleventh lens element L11 having positive power and a convex surface facing the object side. The eleventh lens element L11 has two aspheric surfaces.

  In the zoom lens system according to Embodiment 2, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves toward the object side while drawing a convex locus on the image side. The lens group G2 moves toward the image side with a convex locus on the image side, the third lens group G3 moves monotonously toward the object side, and the fourth lens group G4 draws a convex locus on the object side. Move slightly to the object side. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. Each lens group moves along the optical axis such that the distance between the group G4 increases and the distance between the fourth lens group G4 and the image plane S increases.

  In focusing from the infinitely focused state to the close object focused state, the fourth lens group G4 moves to the object side along the optical axis.

  In the zoom lens system according to Embodiment 2, the ninth lens element L9 and the tenth lens element L10, which are some sub-lens groups of the third lens group G3, are moved in a direction orthogonal to the optical axis. It is possible to correct image point movement due to vibration of the entire system, that is, to optically correct image blur due to camera shake, vibration or the like.

  The zoom lens system according to Embodiment 3 includes a front group GA and a rear group GB in order from the object side to the image side. The front group GA includes a first lens group G1 and a second lens group G2 in order from the object side to the image side. The rear group GB includes a third lens group G3 and a fourth lens group G4 in order from the object side to the image side.

  As shown in FIG. 7, the first lens group G1 includes only a positive meniscus first lens element L1 having positive power and a convex surface directed toward the object side.

  The second lens group G2 includes, in order from the object side to the image side, a biconcave second lens element L2 having negative power, and a negative meniscus shape having negative power and a convex surface facing the object side. The third lens element L3 includes a positive meniscus fourth lens element L4 having a positive power and having a convex surface facing the object side. The third lens element L3 has two aspheric surfaces.

  The third lens group G3 has, in order from the object side to the image side, a positive meniscus fifth lens element L5 having a positive power and a convex surface facing the object side, and a biconvex shape having a positive power. A sixth lens element L6; a biconcave seventh lens element L7 having negative power; an aperture stop A; and a negative meniscus eighth lens element having negative power and having a convex surface facing the image side. L8 and a biconvex ninth lens element L9 having positive power. Among these, the sixth lens element L6 and the seventh lens element L7 are cemented. The sixth lens element L6 has an aspheric object side surface, and the eighth lens element L8 has two aspheric surfaces.

  The fourth lens group G4 comprises solely a positive meniscus tenth lens element L10 having positive power and a convex surface facing the object side.

  In the zoom lens system according to Embodiment 3, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves toward the object side while drawing a convex locus on the image side. The lens group G2 monotonously moves to the image side, the third lens group G3 monotonously moves to the object side, and the fourth lens group G4 monotonously moves to the object side. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. Each lens group moves along the optical axis such that the distance between the group G4 increases and the distance between the fourth lens group G4 and the image plane S increases.

  In focusing from the infinitely focused state to the close object focused state, the fourth lens group G4 moves to the object side along the optical axis.

  In the zoom lens system according to Embodiment 3, the eighth lens element L8 and the ninth lens element L9, which are some sub-lens groups of the third lens group G3, are moved in a direction orthogonal to the optical axis. It is possible to correct image point movement due to vibration of the entire system, that is, to optically correct image blur due to camera shake, vibration or the like.

  The zoom lens system according to Embodiment 4 includes a front group GA and a rear group GB in order from the object side to the image side. The front group GA includes only the first lens group G1. The rear group GB includes a second lens group G2 and a third lens group G3 in order from the object side to the image side.

  As shown in FIG. 10, the first lens group G1 has a negative meniscus first lens element L1 having a negative power and a convex surface facing the object side in order from the object side to the image side. A negative meniscus second lens element L2 having power and having a convex surface facing the object side, and a positive meniscus third lens element L3 having positive power and having a convex surface facing the object side. The second lens element L2 has two aspheric surfaces.

  The second lens group G2 has, in order from the object side to the image side, a positive meniscus fourth lens element L4 having a positive power and a convex surface facing the object side, and a biconvex shape having a positive power. A fifth lens element L5, a biconcave sixth lens element L6 having negative power, an aperture stop A, and a negative meniscus seventh lens element having negative power and having a convex surface facing the image side L7 and a biconvex eighth lens element L8 having a positive power. Among these, the fifth lens element L5 and the sixth lens element L6 are cemented. The fifth lens element L5 has an aspheric object side surface, and the seventh lens element L7 has both aspheric surfaces.

  The third lens group G3 comprises solely a positive meniscus ninth lens element L9 having positive power and a convex surface facing the object side.

  In the zoom lens system according to Embodiment 4, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves toward the object side along a locus convex to the image side, The lens group G2 monotonously moves toward the object side, and the third lens group G3 moves toward the image side while drawing a locus convex toward the object side. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 decreases, the distance between the second lens group G2 and the third lens group G3 increases, and the third lens group G3 and the image plane S Each lens group moves along the optical axis so that the distance between the two and the first lens group decreases.

  In focusing from the infinitely focused state to the close object focused state, the third lens group G3 moves toward the object side along the optical axis.

  In the zoom lens system according to Embodiment 4, the seventh lens element L7 and the eighth lens element L8, which are some sub-lens groups of the second lens group G2, are moved in a direction orthogonal to the optical axis. It is possible to correct image point movement due to vibration of the entire system, that is, to optically correct image blur due to camera shake, vibration or the like.

  The zoom lens system according to Embodiment 5 includes a front group GA and a rear group GB in order from the object side to the image side. The front group GA includes a first lens group G1 and a second lens group G2 in order from the object side to the image side. The rear group GB includes a third lens group G3 and a fourth lens group G4 in order from the object side to the image side.

  As shown in FIG. 13, the first lens group G1 comprises only a positive meniscus first lens element L1 having positive power and a convex surface facing the object side.

  The second lens group G2 has negative power in order from the object side to the image side, a negative meniscus second lens element L2 having a convex surface directed toward the object side, and has negative power. And a negative meniscus third lens element L3 having a convex surface facing the surface, and a positive meniscus fourth lens element L4 having a positive power and having a convex surface facing the object side. The third lens element L3 has two aspheric surfaces.

  The third lens group G3 has, in order from the object side to the image side, a positive meniscus fifth lens element L5 having a positive power and a convex surface facing the object side, and a biconvex shape having a positive power. A sixth lens element L6; a biconcave seventh lens element L7 having negative power; an aperture stop A; and a negative meniscus eighth lens element having negative power and having a convex surface facing the image side. L8 and a biconvex ninth lens element L9 having positive power. Among these, the sixth lens element L6 and the seventh lens element L7 are cemented. The sixth lens element L6 has an aspheric object side surface, and the eighth lens element L8 has two aspheric surfaces.

  The fourth lens group G4 comprises solely a positive meniscus tenth lens element L10 having positive power and a convex surface facing the object side.

  In the zoom lens system according to Embodiment 5, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves slightly toward the image side while drawing a convex locus on the image side, The second lens group G2 moves toward the image side along a convex locus on the image side, the third lens group G3 moves toward the object side monotonously, and the fourth lens group G4 moves toward the object side monotonously. To do. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. Each lens group moves along the optical axis such that the distance between the group G4 increases and the distance between the fourth lens group G4 and the image plane S increases.

  In focusing from the infinitely focused state to the close object focused state, the fourth lens group G4 moves to the object side along the optical axis.

  In the zoom lens system according to Embodiment 5, the eighth lens element L8 and the ninth lens element L9, which are some sub-lens groups of the third lens group G3, are moved in a direction orthogonal to the optical axis. It is possible to correct image point movement due to vibration of the entire system, that is, to optically correct image blur due to camera shake, vibration or the like.

  The zoom lens system according to Embodiment 6 includes a front group GA and a rear group GB in order from the object side to the image side. The front group GA includes a first lens group G1 and a second lens group G2 in order from the object side to the image side. The rear group GB includes a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in order from the object side to the image side.

  As shown in FIG. 16, the first lens group G1 comprises solely a positive meniscus first lens element L1 having positive power and a convex surface facing the object side.

  The second lens group G2 has negative power in order from the object side to the image side, a negative meniscus second lens element L2 having a convex surface facing the object side, and a biconcave shape having negative power. The third lens element L3 includes a positive meniscus fourth lens element L4 having a positive power and having a convex surface facing the object side. The third lens element L3 has two aspheric surfaces.

  The third lens group G3 has, in order from the object side to the image side, a positive meniscus fifth lens element L5 having a positive power and a convex surface facing the object side, and a biconvex shape having a positive power. A sixth lens element L6; a biconcave seventh lens element L7 having negative power; an aperture stop A; and a negative meniscus eighth lens element having negative power and having a convex surface facing the image side. L8 and a biconvex ninth lens element L9 having positive power. Among these, the sixth lens element L6 and the seventh lens element L7 are cemented. The sixth lens element L6 has an aspheric object side surface, and the eighth lens element L8 has two aspheric surfaces.

  The fourth lens group G4 comprises solely a bi-concave tenth lens element L10 having negative power.

  The fifth lens group G5 comprises solely a positive meniscus eleventh lens element L11 having positive power and a convex surface facing the object side.

  In the zoom lens system according to Embodiment 6, during zooming from the wide-angle end to the telephoto end during imaging, the first lens group G1 moves toward the image side along a locus convex to the image side, The lens group G2 moves toward the image side with a convex locus on the image side, the third lens group G3 moves monotonously toward the object side, and the fourth lens group G4 draws a convex locus on the object side. The fifth lens group G5 moves slightly toward the object side while drawing a convex locus on the object side. That is, during zooming, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group G3 and the fourth lens. Each lens group has an optical axis so that the distance between the group G4 increases, the distance between the fourth lens group G4 and the fifth lens group G5 decreases, and the distance between the fifth lens group G5 and the image plane S increases. Move along each.

  In focusing from the infinitely focused state to the close object focused state, the fourth lens group G4 moves to the image side along the optical axis.

  In the zoom lens system according to Embodiment 6, the eighth lens element L8 and the ninth lens element L9, which are some sub-lens groups of the third lens group G3, are moved in a direction orthogonal to the optical axis. It is possible to correct image point movement due to vibration of the entire system, that is, to optically correct image blur due to camera shake, vibration or the like.

  The zoom lens systems according to Embodiments 1 to 6 include, in order from the object side to the image side, a front group having a negative power as a whole and a rear group having a positive power as a whole, and a wide angle during imaging. During zooming from the end to the telephoto end, at least the front group moves along the optical axis, and the first lens group located on the most object side in the front group is composed of three or less lens elements, and the rear group However, since it has a lens group having an aperture stop between lens elements that do not change the air interval during zooming, the diameter of the lens element located immediately on the object side and immediately on the image side of the aperture stop should be reduced. Can do.

  In particular, the reduction in the diameter of the lens element located immediately on the object side and the immediate image side of the aperture stop is a reduction in the diameter of the lens elements constituting the lens group that moves together with the aperture stop during zooming. It is effective for.

  Further, since the diameter of the lens element constituting the rear group is smaller than the diameter of the lens element constituting the front group, the diameter of the lens group for correcting image blur can be reduced.

  Further, since the lens group for correcting the image blur is a sub-lens group of a part of the lens group that moves together with the aperture stop during zooming, the image blur is caused by a lens element having a smaller diameter. Can be corrected.

  In particular, in the zoom lens systems according to Embodiments 2 to 6, the sub lens group for correcting the image blur is positioned on the image side with respect to the aperture stop. In the zoom lens system according to Embodiments 2 to 6 capable of wide-angle shooting, the diameter of the sub lens group is small even when the off-axis light beam of the lens element on the object side of the aperture stop passes through a high position. The entire zoom lens system can be reduced in size.

  In the zoom lens systems according to Embodiments 1 to 6, the front group includes a lens group having negative power, and the lens group having negative power includes two or more lens elements. If the lens group having the negative power is composed of a single lens element, it is difficult to improve the performance of the zoom lens system because aberration fluctuations during zooming become too large. Further, when the lens group having the negative power is composed of five or less lens elements, it is more effective to shorten the entire lens length and to reduce the size of the zoom lens system. Further, when the lens group having negative power is composed of four or less lens elements, and one or two lens elements having positive power are included, the zoom lens system can be further reduced in size and performance. Can be realized.

  In addition, since the lens element disposed on the most object side of the lens group having negative power has negative power, widening of the angle becomes easy and back focus during zooming can be easily ensured.

  In the zoom lens systems according to Embodiments 1 to 6, since the lens group including the aperture stop includes at least one cemented lens element, the holding mechanism for the plurality of lens groups is simplified, and the lens group including the aperture stop Can be easily reduced in size.

  In the zoom lens systems according to Embodiments 1 to 6, since the lens group having the positive power is disposed on the most image side, the telecentricity of light incident on the image sensor can be improved, and the image sensor It is possible to suppress a decrease in the amount of peripheral light due to the structure.

  In the zoom lens systems according to Embodiments 1 to 6, the object side of the image plane S (between the image plane S and the most image side lens surface of the lens group disposed on the most image side) is only air. Although configured, a substantially parallel flat plate equivalent to an optical low-pass filter, a face plate of an image sensor, or the like may be provided.

  Each lens group constituting the zoom lens system according to Embodiments 1 to 6 includes a refractive lens element that deflects incident light by refraction (that is, a type in which deflection is performed at an interface between media having different refractive indexes). However, the present invention is not limited to this. For example, a diffractive lens element that deflects incident light by diffraction, a refractive / diffractive hybrid lens element that deflects incident light by a combination of diffractive action and refractive action, and a refractive index that deflects incident light according to the refractive index distribution in the medium Each lens group may be composed of a distributed lens element or the like. In particular, in a refractive / diffractive hybrid lens element, it is preferable to form a diffractive structure at the interface of media having different refractive indexes, since the wavelength dependency of diffraction efficiency is improved.

  The following description is given for conditions preferred to be satisfied by a zoom lens system like the zoom lens systems according to Embodiments 1 to 6. A plurality of preferable conditions are defined for the zoom lens system according to each embodiment, but a zoom lens system configuration that satisfies all of the plurality of conditions is most desirable. However, by satisfying individual conditions, it is possible to obtain a zoom lens system that exhibits the corresponding effects.

For example, a zoom lens system such as the zoom lens systems according to Embodiments 1 to 6 satisfies the following condition (1) in order to effectively reduce the size thereof.
0.1 <BF / f _W <2.0 (1)
However,
ω _W > 72 °
FNO _W <2.9
here,
BF: Back focus of the entire system at the wide angle end
f _W : focal length of the entire system at the wide-angle end,
ω _W : Angle of view at the wide-angle end,
FNO _W : F number at the wide-angle end.

  Condition (1) is that the back focus (BF) representing the distance in terms of air between the image side surface of the lens element having the power located on the most image side among the lens elements constituting the zoom lens system and the image plane is set. It is a condition to prescribe. If the upper limit of the condition (1) is exceeded, the back focus becomes long, so that the entire lens length becomes too long and the zoom lens system becomes large. On the contrary, if the lower limit of the condition (1) is not reached, the image plane and the image side surface of the lens element having the power located on the most image side become too close, and the lens element or image pickup having the power located on the most image side is too close. It becomes difficult to dispose the element holding mechanism.

In order to further enhance the effect of the condition (1), it is desirable to satisfy at least one of the following conditions (1) ′ and (1) ″.
0.2 <BF / f _W (1) ′
BF / f _W <1.7 (1) ''

In order to effectively reduce the size of the zoom lens system such as the zoom lens systems according to Embodiments 1 to 6, it is preferable that the following condition (2) is satisfied.
0.01 <THs / Rmin <1.00 (2)
here,
THs: Center distance between the surface located on the object side closest to the aperture stop and the aperture stop,
Rmin: a lens group that is located on the object side closest to the aperture stop and moves during zooming from the wide-angle end to the telephoto end during imaging. Value.

  In the condition (2) and the condition (3) described later, the lens group that is located on the object side closest to the aperture stop and moves during zooming from the wide-angle end to the telephoto end during imaging is the entire lens group. It may be a partial lens group of the lens group.

  Condition (2) is that, in the lens group that is located on the object side closest to the aperture stop and moves during zooming, the negative radius of the surface having negative power has a positive and minimum value of curvature, and the aperture stop This is a condition that defines the ratio between the surface located on the closest object side and the center distance between the aperture stop. If the upper limit of the condition (2) is exceeded, the radius of curvature becomes small, so the flare becomes large and the image quality deteriorates. On the contrary, if the lower limit of the condition (2) is not reached, the curvature radius becomes large, so that the curvature of field becomes large.

In order to further enhance the effect of the condition (2), it is desirable to satisfy at least one of the following conditions (2) ′ and (2) ″.
0.05 <THs / Rmin (2) ′
THs / Rmin <0.70 (2) ''

In order to effectively reduce the size of the zoom lens system such as the zoom lens systems according to Embodiments 1 to 6, it is preferable that the following condition (3) is satisfied.
0.01 <TH_GA / G_SUM <1.00 (3)
here,
TH_GA: an optical axis between a lens group that is located on the object side closest to the aperture stop and moves during zooming from the wide-angle end to the telephoto end during imaging, and a lens group that is located on the object side closest to the lens group Minimum spacing above,
G_SUM: Thickness on the optical axis of a lens group that is located on the object side closest to the aperture stop and moves during zooming from the wide-angle end to the telephoto end during imaging.

  Condition (3) is that the minimum distance on the optical axis between the lens group that is located on the object side closest to the aperture stop and moves during zooming and the lens group that is located on the object side closest to the lens group, This is a condition that defines the ratio of the lens group located on the object side closest to the aperture stop and moving on zooming to the thickness on the optical axis. If the upper limit of condition (3) is exceeded, the thickness of the lens group that moves during zooming is too small, the lens group becomes too thin, and aberration correction becomes difficult. On the other hand, if the lower limit of condition (3) is not reached, the thickness of the lens group that moves during zooming becomes too large, and the thickness of the lens barrel when retracted becomes large.

In order to further enhance the effect of the condition (3), it is desirable to satisfy at least one of the following conditions (3) ′ and (3) ″.
0.05 <TH_GA / G_SUM (3) ′
TH_GA / G_SUM <0.30 (3) ''

(Embodiment 7)
FIG. 19 is a schematic configuration diagram of a digital still camera according to the seventh embodiment. In FIG. 19, the digital still camera includes an image pickup apparatus including a zoom lens system 1 and an image pickup device 2 that is a CCD, a liquid crystal monitor 3, and a housing 4. As the zoom lens system 1, the zoom lens system according to Embodiment 4 is used. In FIG. 19, the zoom lens system 1 includes a first lens group G1, a second lens group G2 including an aperture stop A, and a third lens group G3 in order from the object side to the image side. In the housing 4, the zoom lens system 1 is disposed on the front side, and the imaging element 2 is disposed on the rear side of the zoom lens system 1. A liquid crystal monitor 3 is disposed on the rear side of the housing 4, and an optical image of the subject by the zoom lens system 1 is formed on the image plane S.

  The lens barrel includes a main lens barrel 5, a movable lens barrel 6, and a cylindrical cam 7. When the cylindrical cam 7 is rotated, the first lens group G1, the second lens group G2 including the aperture stop A, and the third lens group G3 move to predetermined positions based on the image sensor 2, and from the wide angle end to the telephoto end. Up to zooming can be performed. The third lens group G3 is movable in the optical axis direction by a focus adjustment driving device.

  At the time of image blur correction, some sub-lens groups of the second lens group G2 for image blur correction are moved in a direction orthogonal to the optical axis by the image blur correction lens driving device 8, and an image caused by vibration of the entire system Point movement is corrected.

  Thus, by using the zoom lens system according to Embodiment 4 for a digital still camera, it is possible to provide a small digital still camera that has a high ability to correct resolution and curvature of field and has a short overall lens length when not in use. it can. In the digital still camera shown in FIG. 19, any of the zoom lens systems according to Embodiments 1 to 3, 5 and 6 may be used instead of the zoom lens system according to Embodiment 4. Further, the optical system of the digital still camera shown in FIG. 19 can also be used for a digital video camera for moving images. In this case, not only a still image but also a moving image with high resolution can be taken.

  In the digital still camera according to the seventh embodiment, the zoom lens system according to the first to sixth embodiments is shown as the zoom lens system 1. However, these zoom lens systems need to use all zooming areas. There is no. That is, a range in which the optical performance is ensured according to a desired zooming area may be cut out and used as a zoom lens system having a lower magnification than the zoom lens system described in the first to sixth embodiments.

  Furthermore, in the seventh embodiment, an example in which the zoom lens system is applied to a so-called collapsible lens barrel is shown, but the present invention is not limited to this. For example, a prism having an internal reflection surface or a surface reflection mirror may be disposed at an arbitrary position such as in the first lens group G1, and the zoom lens system may be applied to a so-called bent lens barrel. Furthermore, in the seventh embodiment, some lens groups constituting the zoom lens system, such as the entire second lens group G2, the entire third lens group G3, and a part of the second lens group G2, are irradiated with light when retracted. The zoom lens system may be applied to a so-called sliding lens barrel that is retracted from the axis.

  In the digital still camera according to the seventh embodiment, the zoom lens system according to the first to sixth embodiments is used. However, the present invention is not limited to this.

  An imaging apparatus including the zoom lens system according to Embodiments 1 to 6 described above and an imaging element such as a CCD or a CMOS is used as a mobile phone device, a PDA (Personal Digital Assistance), a surveillance camera in a surveillance system, a Web The present invention can also be applied to imaging devices such as cameras and in-vehicle cameras, and camera systems including these cameras.

ここで、ｈは光軸からの高さ、κは円錐定数、Ａ４、Ａ６、Ａ８及びＡ１０は、それぞれ４次、６次、８次及び１０次の非球面係数である。 Hereinafter, numerical examples in which the zoom lens systems according to Embodiments 1 to 6 are specifically implemented will be described. In each numerical example, the unit of length in the table is “mm”, and the unit of angle of view is “°”. In each numerical example, r is a radius of curvature, d is a surface interval, nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line. In each numerical example, the surface marked with * is an aspherical surface, and the aspherical shape is defined by the following equation.

Here, h is the height from the optical axis, κ is the conic constant, and A4, A6, A8 and A10 are the fourth, sixth, eighth and tenth aspherical coefficients, respectively.

  2, 5, 8, 11, 14, and 17 are longitudinal aberration diagrams of the zoom lens systems according to Embodiments 1, 2, 3, 4, 5, and 6, respectively.

  In each longitudinal aberration diagram, (a) shows the aberration at the wide angle end, (b) shows the intermediate position, and (c) shows the aberration at the telephoto end. Each longitudinal aberration diagram shows spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)) in order from the left side. In the spherical aberration diagram, the vertical axis represents the F number (indicated by F in the figure), the solid line is the d line (d-line), the short broken line is the F line (F-line), and the long broken line is the C line (C- line). In the astigmatism diagram, the vertical axis represents the image height (indicated by H in the figure), the solid line represents the sagittal plane (indicated by s), and the broken line represents the meridional plane (indicated by m in the figure). is there. In the distortion diagram, the vertical axis represents the image height (indicated by H in the figure).

  3, 6, 9, 12, 15, and 18 are lateral aberration diagrams at the telephoto end of the zoom lens systems according to Embodiments 1, 2, 3, 4, 5, and 6, respectively.

  In each lateral aberration diagram, the upper three aberration diagrams show the basic state where image blur correction at the telephoto end is not performed, and the lower three aberration diagrams show the sub lens group for image blur correction in a direction perpendicular to the optical axis. This corresponds to the image blur correction state at the telephoto end moved by a predetermined amount. Of the lateral aberration diagrams in the basic state, the upper row shows the lateral aberration at the image point of 70% of the maximum image height, the middle row shows the lateral aberration at the axial image point, and the lower row shows the lateral aberration at the image point of -70% of the maximum image height. Respectively. In each lateral aberration diagram in the image blur correction state, the upper row shows the lateral aberration at the image point of 70% of the maximum image height, the middle row shows the lateral aberration at the axial image point, and the lower row shows the image point at −70% of the maximum image height. Each corresponds to lateral aberration. In each lateral aberration diagram, the horizontal axis represents the distance from the principal ray on the pupil plane, the solid line is the d line (d-line), the short broken line is the F line (F-line), and the long broken line is the C line ( C-line) characteristics. In each lateral aberration diagram, the meridional plane is a plane including the optical axis of the first lens group G1 and the optical axis of the sub lens group.

In the zoom lens system of each example, the amount of movement in the direction perpendicular to the optical axis of the sub lens group that corrects the image blur correction state of 0.6 ° at the telephoto end is as follows.
Example Travel (mm)
1 0.18
2 0.49
3 0.47
4 0.15
5 0.20
6 0.30

  As can be seen from the respective lateral aberration diagrams, the symmetry of the lateral aberration at the axial image point is good. Further, when the lateral aberration at the + 70% image point and the lateral aberration at the -70% image point are compared in the basic state, the curvature is small and the inclinations of the aberration curves are almost equal. It can be seen that the aberration is small. This means that sufficient imaging performance is obtained even in the image blur correction state. When the image blur correction angle of the zoom lens system is the same, the amount of parallel movement required for image blur correction decreases as the focal length of the entire zoom lens system decreases. Therefore, sufficient image blur correction can be performed for image blur correction angles up to about 0.6 ° at any zoom position.

(Numerical example 1)
The zoom lens system of Numerical Example 1 corresponds to Embodiment 1 shown in FIG. Table 1 shows surface data of the zoom lens system of Numerical Example 1, Table 2 shows aspheric data, Table 3 shows various data, Table 4 shows single lens data, Table 5 shows zoom lens group data, and Zoom Lens Group magnification is shown in Table 6.

Table 1 (surface data)

Surface number rd nd vd
Object ∞
1 43.07000 2.42900 1.86746 41.6
2 -171.16200 Variable
3 -145.35100 0.40000 1.79796 30.0
4 11.48700 2.39000
5 * 78.37800 0.50000 1.69384 53.1
6 * 8.10400 1.54900
7 10.90800 1.61400 1.99000 19.0
8 21.16500 Variable
9 6.60700 1.72900 1.88312 40.7
10 49.03600 0.15000
11 * 6.55200 1.62200 1.77200 50.0
12 -26.73400 0.00800 1.56732 42.8
13 -26.73400 0.30000 1.91193 25.9
14 4.00400 1.44400
15 (Aperture) ∞ 2.83400
16 -4.72500 0.40000 1.48700 82.0
17 -6.85300 0.10000
18 32.39500 1.11500 1.48778 81.8
19 -9.16300 Variable
20 10.76400 1.27600 1.59684 46.7
21 37.04100 Variable image plane ∞

Table 2 (Aspheric data)

5th page
K = 4.81915E + 00, A4 = -1.40483E-04, A6 = 2.44424E-06, A8 = 2.91612E-08
A10 = -5.16642E-10
6th page
K = 0.00000E + 00, A4 = -2.07167E-04, A6 = -2.33689E-06, A8 = 2.03945E-07
A10 = -3.22758E-09
11th page
K = 0.00000E + 00, A4 = -3.44900E-04, A6 = -7.00104E-06, A8 = -2.70187E-06
A10 = 1.79925E-07

Table 3 (various data)

Zoom ratio 4.54235
Wide angle Medium telephoto Focal length 4.7866 10.0154 21.7424
F number 2.40244 3.16366 4.84039
Angle of View 41.0250 21.8816 10.1853
Image height 3.5600 3.9000 3.9000
Total lens length 48.7835 42.0616 48.0126
BF 3.88128 5.01692 5.17959
d2 0.2508 3.0722 5.8028
d8 22.1323 7.7832 0.5039
d19 2.6591 6.3293 16.6663
d21 2.9813 4.1170 4.3042
Entrance pupil position 12.5040 15.8077 19.3686
Exit pupil position -11.6118 -20.9753 -150.8812
Front principal point position 15.8118 21.9639 38.0818
Rear principal point position 43.9969 32.0462 26.2702

Table 4 (Single lens data)

Lens Start surface Focal length
1 1 39.8786
2 3 -13.3260
3 5 -13.0648
4 7 21.0851
5 9 8.4843
6 11 6.9643
7 13 -3.8010
8 16 -33.2948
9 18 14.7733
10 20 24.9695

Table 5 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 39.87859 2.42900 0.26288 1.38430
2 3 -9.57293 6.45300 0.57604 1.79012
3 9 12.47936 9.70200 0.89986 0.23313
4 20 24.96952 1.27600 -0.32150 0.16967

Table 6 (zoom lens group magnification)

1 1 0.00000 0.00000 0.00000
2 3 -0.33667 -0.37376 -0.41836
3 9 -0.44551 -0.89027 -1.74168
4 20 0.80025 0.75477 0.74826

(Numerical example 2)
The zoom lens system of Numerical Example 2 corresponds to Embodiment 2 shown in FIG. Surface data of the zoom lens system of Numerical Example 2 are shown in Table 7, aspherical data in Table 8, various data in Table 9, single lens data in Table 10, zoom lens group data in Table 11, and zoom lens. Group magnification is shown in Table 12.

Table 7 (surface data)

Surface number rd nd vd
Object ∞
1 26.21600 0.50000 1.99000 19.0
2 18.18000 0.01000 1.56732 42.8
3 18.18000 3.21800 1.88300 40.8
4 92.50300 Variable
5 * 33.92600 0.40000 1.88300 40.8
6 * 7.70500 3.11600
7 -200.00000 0.50000 1.88237 40.8
8 9.80200 1.29700
9 13.12700 1.79100 1.99000 19.0
10 55.26400 Variable
11 * 7.74600 1.53700 1.84075 41.6
12 282.98100 0.15000
13 6.51100 1.80300 1.72141 51.5
14 -13.24500 0.00800 1.56732 42.8
15 -13.24500 0.30000 1.91333 30.2
16 4.60600 1.44200
17 (Aperture) ∞ 1.70400
18 * -5.24200 0.40000 1.60770 47.8
19 * -8.58700 0.10000
20 17.82200 1.50100 1.48700 82.0
21 -9.15600 Variable
22 * 8.25400 1.19500 1.48714 82.0
23 * 16.35200 Variable image plane ∞

Table 8 (Aspherical data)

5th page
K = 0.00000E + 00, A4 = -2.81259E-04, A6 = 6.17760E-06, A8 = -7.73502E-08
A10 = 3.26589E-10
6th page
K = 0.00000E + 00, A4 = -3.15341E-04, A6 = -5.45723E-06, A8 = 2.18153E-07
A10 = -5.06461E-09
11th page
K = 0.00000E + 00, A4 = -3.66737E-05, A6 = -6.96061E-06, A8 = 6.76429E-07
A10 = -2.83645E-08
18th page
K = 0.00000E + 00, A4 = 5.69582E-03, A6 = -1.65211E-04, A8 = -3.59569E-06
A10 = 4.26675E-08
19th page
K = 0.00000E + 00, A4 = 5.13051E-03, A6 = -1.88291E-04, A8 = 0.00000E + 00
A10 = 0.00000E + 00
22nd page
K = 0.00000E + 00, A4 = -5.79573E-04, A6 = 2.86286E-05, A8 = -7.17748E-07
A10 = 0.00000E + 00
23rd page
K = 0.00000E + 00, A4 = -5.45657E-04, A6 = 3.58017E-05, A8 = -8.85125E-07
A10 = 0.00000E + 00

Table 9 (various data)

Zoom ratio 8.74684
Wide angle Medium telephoto Focal length 4.4072 13.0564 38.5491
F number 2.67906 3.63814 5.50315
Angle of view 43.3093 16.8058 5.6653
Image height 3.5600 3.9000 3.9000
Total lens length 52.5477 51.9250 65.1990
BF 4.97926 8.41408 5.54771
d4 0.2508 10.0642 18.9272
d10 22.7508 6.6340 0.5008
d21 3.5948 5.8407 19.2513
d23 4.0474 7.4741 4.6816
Entrance pupil position 12.6459 33.5503 72.9609
Exit pupil position -9.7505 -13.5986 -71.0864
Front principal point position 15.7345 38.8625 92.1187
Rear principal point position 48.1405 38.8686 26.6499

Table 10 (Single lens data)

Lens Start surface Focal length
1 1 -61.8216
2 3 25.1152
3 5 -11.3714
4 7 -10.5779
5 9 17.0302
6 11 9.4484
7 13 6.2915
8 15 -3.7121
9 18 -23.1921
10 20 12.6506
11 22 32.6361

Table 11 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 43.48100 3.72800 -0.87669 0.93857
2 5 -8.23632 7.10400 0.59525 1.76394
3 11 12.81469 8.94500 0.69607 0.87156
4 22 32.63613 1.19500 -0.78127 -0.35277

Table 12 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 5 -0.26057 -0.37789 -0.63685
3 11 -0.48624 -1.14375 -1.77885
4 22 0.80001 0.69476 0.78259

(Numerical Example 3)
The zoom lens system of Numerical Example 3 corresponds to Embodiment 3 shown in FIG. Surface data of the zoom lens system of Numerical Example 3 are shown in Table 13, aspherical data in Table 14, various data in Table 15, single lens data in Table 16, zoom lens group data in Table 17, and zoom lens. Group magnification is shown in Table 18.

Table 13 (surface data)

Surface number rd nd vd
Object ∞
1 22.96500 3.33300 1.65368 59.1
2 179.71200 Variable
3 -1718.22800 0.40000 1.67154 57.3
4 7.65800 3.39200
5 * 80.38500 0.50000 1.69384 53.1
6 * 11.18300 1.65000
7 14.83800 1.32200 1.93902 25.0
8 39.23100 Variable
9 7.58500 2.25300 1.85318 30.2
10 65.22800 0.15700
11 * 8.67800 1.77900 1.77200 50.0
12 -25.94900 0.00800 1.56732 42.8
13 -25.94900 0.30000 1.92639 20.8
14 5.19600 1.63500
15 (Aperture) ∞ 1.47300
16 * -11.24200 0.40000 1.50379 67.4
17 * -20.45500 0.10000
18 30.80700 1.27200 1.48700 82.0
19 -13.25000 Variable
20 16.60800 1.11400 1.82613 23.9
21 111.90200 Variable image plane ∞

Table 14 (Aspherical data)

5th page
K = 0.00000E + 00, A4 = -1.35325E-04, A6 = 9.21890E-07, A8 = 5.32851E-08
A10 = -7.43092E-10
6th page
K = 0.00000E + 00, A4 = -2.57646E-04, A6 = -1.83474E-06, A8 = 1.26617E-07
A10 = -2.03744E-09
11th page
K = 0.00000E + 00, A4 = -2.96873E-04, A6 = 1.43464E-07, A8 = -1.07913E-06
A10 = 4.06193E-08
16th page
K = 0.00000E + 00, A4 = 2.21390E-05, A6 = -9.44767E-06, A8 = 0.00000E + 00
A10 = 0.00000E + 00
17th page
K = 0.00000E + 00, A4 = 7.98058E-05, A6 = -6.02891E-06, A8 = 0.00000E + 00
A10 = 0.00000E + 00

Table 15 (various data)

Zoom ratio 4.64640
Wide angle Medium telephoto Focal length 5.3507 8.5305 24.8617
F number 1.97246 2.24636 3.35695
Angle of view 36.8515 25.4297 8.9346
Image height 3.5600 3.9000 3.9000
Total lens length 52.9412 48.5383 54.7316
BF 6.46405 7.55581 8.50477
d2 0.3508 3.6006 11.2367
d8 22.3793 12.4426 0.5008
d19 2.6591 3.8513 13.4013
d21 5.5441 6.6294 7.6038
Entrance pupil position 14.5422 20.0537 38.9958
Exit pupil position -8.0381 -10.2366 -54.2795
Front principal point position 17.9187 24.4943 54.0126
Rear principal point position 47.5905 40.0078 29.8699

Table 16 (single lens data)

Lens Start surface Focal length
1 1 39.9436
2 3 -11.3520
3 5 -18.7776
4 7 24.7637
5 9 9.8823
6 11 8.6167
7 13 -4.6516
8 16 -50.2756
9 18 19.2065
10 20 23.4829

Table 17 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 39.94361 3.33300 -0.29283 1.04146
2 3 -10.25482 7.26400 0.13669 0.86783
3 9 14.23150 9.37700 -0.59385 0.82964
4 20 23.48292 1.11400 -0.10576 0.40142

Table 18 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 3 -0.38108 -0.43343 -0.63997
3 9 -0.50623 -0.76052 -1.60098
4 20 0.69439 0.64790 0.60749

(Numerical example 4)
The zoom lens system of Numerical Example 4 corresponds to Embodiment 4 shown in FIG. The surface data of the zoom lens system of Numerical Example 4 is shown in Table 19, the aspheric data is shown in Table 20, the various data is shown in Table 21, the single lens data is shown in Table 22, the zoom lens group data is shown in Table 23, and the zoom lens. Group magnification is shown in Table 24.

Table 19 (surface data)

Surface number rd nd vd
Object ∞
1 27.51300 0.40000 1.88300 40.8
2 8.81800 3.80100
3 * 62.56100 0.50000 1.85400 40.4
4 * 8.65700 2.65900
5 16.09100 3.41900 1.98580 19.1
6 57.74800 Variable
7 6.86700 2.40400 1.65547 40.2
8 112.14000 0.15000
9 * 7.28200 2.17000 1.76801 49.2
10 -12.16400 0.00800 1.56732 42.8
11 -12.16400 0.30000 1.91084 29.6
12 4.78900 1.57100
13 (Aperture) ∞ 1.33800
14 * -7.85900 0.40000 1.68893 31.1
15 * -11.85000 0.10000
16 10.50600 1.42500 1.49480 80.5
17 -17.73200 Variable
18 10.23700 1.50000 1.48700 82.0
19 47.86500 Variable image plane ∞

Table 20 (Aspheric data)

Third side
K = 4.81915E + 00, A4 = 3.46941E-04, A6 = -1.05286E-05, A8 = 1.98691E-07
A10 = -1.39198E-09
4th page
K = 0.00000E + 00, A4 = 1.47872E-04, A6 = -1.59511E-05, A8 = 3.38338E-07
A10 = -3.56802E-09
9th page
K = 0.00000E + 00, A4 = -2.54018E-04, A6 = -7.77061E-06, A8 = -3.05015E-07
A10 = 4.38948E-09
14th page
K = 0.00000E + 00, A4 = 5.53123E-03, A6 = -1.72108E-04, A8 = 2.25238E-06
A10 = -1.26780E-07
15th page
K = 0.00000E + 00, A4 = 5.19401E-03, A6 = -1.40377E-04, A8 = 0.00000E + 00
A10 = 0.00000E + 00

Table 21 (various data)

Zoom ratio 5.04495
Wide angle Medium telephoto Focal length 3.4068 7.6604 17.1870
F number 2.06260 3.13606 5.59286
Angle of view 51.6200 28.5778 12.8972
Image height 3.5600 3.9000 3.9000
Total lens length 53.9727 44.9594 54.5285
BF 5.06756 5.24435 5.00249
d6 24.1010 7.6281 0.5008
d17 2.6591 9.9419 26.8802
d19 4.1367 4.2982 4.1141
Entrance pupil position 8.7001 7.8293 7.1424
Exit pupil position -8.0213 -25.6001 242.5247
Front principal point position 11.2202 13.5872 25.5731
Rear principal point position 50.5659 37.2989 37.3415

Table 22 (Single lens data)

Lens Start surface Focal length
1 1 -14.8457
2 3 -11.8155
3 5 21.7421
4 7 11.0599
5 9 6.2331
6 11 -3.7410
7 14 -35.3148
8 16 13.5596
9 18 26.3947

Table 23 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -9.94520 10.77900 0.64717 2.35908
2 7 13.27739 9.86600 0.26957 1.32671
3 18 26.39474 1.50000 -0.27090 0.23336

Table 24 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 7 -0.45072 -1.02249 -2.26650
3 18 0.76002 0.75332 0.76249

(Numerical example 5)
The zoom lens system of Numerical Example 5 corresponds to Embodiment 5 shown in FIG. The surface data of the zoom lens system of Numerical Example 5 are shown in Table 25, the aspherical data in Table 26, the various data in Table 27, the single lens data in Table 28, the zoom lens group data in Table 29, and the zoom lens. Group magnification is shown in Table 30.

Table 25 (surface data)

Surface number rd nd vd
Object ∞
1 33.07800 3.36100 1.88467 40.0
2 187.67800 Variable
3 243.88800 0.40000 1.86731 41.6
4 8.61100 3.11600
5 * 33.44100 0.50000 1.69384 53.1
6 * 8.22500 2.69300
7 13.74400 1.38600 1.96213 20.9
8 28.06900 Variable
9 7.59800 1.56000 1.88723 38.8
10 96.35200 0.15000
11 * 7.91600 2.04000 1.77200 50.0
12 -15.52400 0.00800 1.56732 42.8
13 -15.52400 0.30000 1.92748 27.0
14 4.66600 1.33300
15 (Aperture) ∞ 1.97500
16 * -5.46000 0.40000 1.53704 51.0
17 * -7.88100 0.10000
18 19.66200 1.36600 1.48716 81.8
19 -9.92200 Variable
20 11.18300 1.79300 1.50177 68.8
21 133.12300 Variable image plane ∞

Table 26 (Aspherical data)

5th page
K = 4.81915E + 00, A4 = -1.52082E-04, A6 = 2.33654E-06, A8 = 5.39756E-08
A10 = -9.02184E-10
6th page
K = 0.00000E + 00, A4 = -3.71267E-04, A6 = -2.17506E-06, A8 = 1.96115E-07
A10 = -3.69473E-09
11th page
K = 0.00000E + 00, A4 = -2.24963E-04, A6 = 1.95144E-06, A8 = -1.85152E-06
A10 = 1.15426E-07
16th page
K = 0.00000E + 00, A4 = 3.66678E-03, A6 = -7.67127E-05, A8 = -2.55219E-06
A10 = 1.02005E-07
17th page
K = 0.00000E + 00, A4 = 3.36746E-03, A6 = -9.35689E-05, A8 = 0.00000E + 00
A10 = 0.00000E + 00

Table 27 (various data)

Zoom ratio 4.54469
Wide angle Medium telephoto Focal length 3.9875 8.1352 18.1220
F number 2.60838 3.50685 5.45930
Angle of view 46.1998 26.5603 12.2314
Image height 3.5600 3.9000 3.9000
Total lens length 53.9504 45.9622 53.7362
BF 3.58967 4.49925 5.57926
d2 0.2508 1.7775 4.8058
d8 23.2415 8.3095 0.5008
d19 4.3874 8.8950 20.3693
d21 2.6840 3.5953 4.6861
Entrance pupil position 11.7203 13.0159 17.1006
Exit pupil position -13.9274 -28.4899 8364.3130
Front principal point position 14.8001 19.1450 35.2618
Rear principal point position 49.9629 37.8270 35.6142

Table 28 (single lens data)

Lens Start surface Focal length
1 1 44.9318
2 3 -10.2999
3 5 -15.8496
4 7 26.7226
5 9 9.2207
6 11 7.0587
7 13 -3.8407
8 16 -35.1233
9 18 13.7442
10 20 24.2120

Table 29 (zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 44.93181 3.36100 -0.37771 1.21797
2 3 -8.45713 8.09500 0.22962 0.90368
3 9 12.92145 9.23200 0.95271 0.96077
4 20 24.21203 1.79300 -0.10896 0.49595

Table 30 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 3 -0.24983 -0.26163 -0.28868
3 9 -0.44504 -0.90984 -1.95132
4 20 0.79817 0.76060 0.71600

(Numerical example 6)
The zoom lens system of Numerical Example 6 corresponds to Embodiment 6 shown in FIG. Surface data of the zoom lens system of Numerical Example 6 are shown in Table 31, aspherical data in Table 32, various data in Table 33, single lens data in Table 34, zoom lens group data in Table 35, and zoom lens. Group magnification is shown in Table 36.

Table 31 (surface data)

Surface number rd nd vd
Object ∞
1 21.76900 2.69100 1.70196 55.4
2 760.72500 Variable
3 398.94100 0.40000 1.68301 56.7
4 7.95900 3.35900
5 * -143.97600 0.50000 1.69384 53.1
6 * 13.38800 1.55500
7 12.30300 1.04100 1.99000 19.0
8 19.96600 Variable
9 8.79600 1.63300 1.90935 24.0
10 154.40800 0.15000
11 * 8.93400 1.63500 1.77200 50.0
12 -18.79700 0.00800 1.56732 42.8
13 -18.79700 0.30000 1.91586 20.2
14 5.66400 1.43000
15 (Aperture) ∞ 1.73100
16 * -6.87300 0.40000 1.54515 52.9
17 * -12.32100 0.10000
18 38.39300 1.51300 1.52453 75.5
19 -8.56900 Variable
20 -97.96800 0.50000 1.52501 70.3
21 20.26200 Variable
22 11.29900 1.58700 1.90813 31.5
23 70.36800 Variable image plane ∞

Table 32 (Aspherical data)

5th page
K = 4.81915E + 00, A4 = -1.21714E-04, A6 = 1.78239E-06, A8 = 4.64027E-08
A10 = -8.88492E-10
6th page
K = 0.00000E + 00, A4 = -1.00118E-04, A6 = 2.42593E-07, A8 = 1.17142E-07
A10 = -1.80097E-09
11th page
K = 0.00000E + 00, A4 = -1.35671E-04, A6 = 1.43215E-06, A8 = -9.27794E-07
A10 = 4.72578E-08
16th page
K = 0.00000E + 00, A4 = 6.27422E-04, A6 = -1.83309E-05, A8 = 0.00000E + 00
A10 = 0.00000E + 00
17th page
K = 0.00000E + 00, A4 = 7.45076E-04, A6 = -1.48304E-05, A8 = 0.00000E + 00
A10 = 0.00000E + 00

Table 33 (various data)

Zoom ratio 4.67974
Wide angle Medium telephoto Focal length 5.4611 11.0999 25.5564
F number 2.50283 3.14065 4.63821
Angle of view 36.9761 19.9589 8.7725
Image height 3.5600 3.9000 3.9000
Total lens length 53.9448 49.1666 53.4744
BF 5.69280 6.04192 5.86093
d2 0.2508 3.6323 6.4315
d8 22.0066 9.2968 0.5008
d19 2.6822 6.9034 17.7393
d21 2.7794 2.7592 2.4089
d23 4.7544 5.0946 4.8407
Entrance pupil position 13.8985 19.8592 24.5511
Exit pupil position -19.9086 -42.5845 352.0867
Front principal point position 18.1946 28.4253 51.9940
Rear principal point position 48.4837 38.0668 27.9180

Table 34 (single lens data)

Lens Start surface Focal length
1 1 31.8773
2 3 -11.8950
3 5 -17.6308
4 7 30.3296
5 9 10.2027
6 11 8.0511
7 13 -4.7246
8 16 -29.2712
9 18 13.5052
10 20 -31.9333
11 22 14.6348

Table 35 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 31.87726 2.69100 -0.04651 1.06575
2 3 -9.01579 6.85500 0.73418 1.70094
3 9 13.63506 8.90000 1.74587 1.82634
4 20 -31.93328 0.50000 0.27128 0.44389
5 22 14.63485 1.58700 -0.15708 0.60871

Table 36 (zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 3 -0.44520 -0.53444 -0.64076
3 9 -0.48179 -0.83162 -1.59318
4 20 1.46778 1.50576 1.47434
5 22 0.54416 0.52031 0.53268

  Table 37 below shows corresponding values of the conditions in the zoom lens systems of the numerical examples.

Table 37 (corresponding values of conditions)

  The zoom lens system according to the present invention can be applied to digital input devices and camera systems such as digital cameras, mobile phone devices, PDAs (Personal Digital Assistance), surveillance cameras in surveillance systems, web cameras, in-vehicle cameras, etc. It is suitable for a photographing optical system that requires high image quality such as a camera.

GA front group GB rear group G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group L1 first lens element L2 second lens element L3 third lens element L4 fourth lens Element L5 5th lens element L6 6th lens element L7 7th lens element L8 8th lens element L9 9th lens element L10 10th lens element L11 11th lens element A Aperture stop S Image surface 1 Zoom lens system 2 Imaging element 3 LCD monitor 4 Housing 5 Main barrel 6 Moving barrel 7 Cylindrical cam 8 Image blur correction lens drive device

Claims (7)

A zoom lens system having a plurality of lens groups each composed of at least one lens element,
From the object side to the image side,
A front group including a first lens group located on the most object side and having negative power as a whole;
A rear group having positive power as a whole,
During zooming from the wide-angle end to the telephoto end during imaging, at least the front group moves along the optical axis,
The first lens group is composed of three or less lens elements,
The rear group has a lens group having an aperture stop between lens elements that do not change the air interval during zooming;
A sub-lens group of a part of the lens group constituting the rear group moves in a direction perpendicular to the optical axis to optically correct image blur;
A zoom lens system that satisfies the following condition (1):
0.1 <BF / f _W <2.0 (1)
However,
ω _W > 72 °
FNO _W <2.9
here,
BF: Back focus of the entire system at the wide-angle end,
f _W : focal length of the entire system at the wide-angle end,
ω _W : Angle of view at the wide-angle end,
FNO _W : F number at the wide-angle end.   The zoom lens system according to claim 1, wherein the front group includes a lens group having negative power, and the lens group having negative power includes two or more lens elements.   The zoom lens system according to claim 2, wherein the lens element disposed on the most object side of the lens group having negative power has negative power.   The zoom lens system according to claim 1, wherein the lens group including the aperture stop includes at least one cemented lens element.   The zoom lens system according to claim 1, wherein a lens group having a positive power is disposed on the most image side. An imaging apparatus capable of outputting an optical image of an object as an electrical image signal,
A zoom lens system that forms an optical image of the object;
An image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
An imaging apparatus, wherein the zoom lens system is the zoom lens system according to claim 1. A camera that converts an optical image of an object into an electrical image signal, and displays and stores the converted image signal;
An image pickup apparatus including a zoom lens system that forms an optical image of an object, and an image sensor that converts an optical image formed by the zoom lens system into an electrical image signal;
The camera according to claim 1, wherein the zoom lens system is the zoom lens system according to claim 1.

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